Components of high-temperature mechanical systems, such as, for example, gas-turbine engines, operate in severe environments. For example, the high-pressure turbine blades, vanes, blade tracks and blade shrouds exposed to hot gases of about 1100 degrees Celsius (C), with short-term peaks greater than about 1550 degrees C.
Components of high-temperature mechanical systems may include a ceramic substrate, or a ceramic matrix composite (CMC) substrate. Some ceramics or CMCs possess excellent high temperature mechanical, physical and chemical properties, and may allow gas turbine engines to operate at higher temperatures than gas turbine engines having superalloy components.